feat(cmd): add --disable-commands flag for command denylist

README.md

@@ -379,6 +379,7 @@ gog keep get <noteId> --account you@yourdomain.com
 - `GOG_COLOR` - Color mode: `auto` (default), `always`, or `never`
 - `GOG_TIMEZONE` - Default output timezone for Calendar/Gmail (IANA name, `UTC`, or `local`)
 - `GOG_ENABLE_COMMANDS` - Comma-separated allowlist of top-level commands (e.g., `calendar,tasks`)
+- `GOG_DISABLE_COMMANDS` - Comma-separated denylist using dot-notation (e.g., `gmail.send`)
 
 ### Config File (JSON5)
 
@@ -435,7 +436,7 @@ gog auth alias unset work
 
 Aliases work anywhere you pass `--account` or `GOG_ACCOUNT` (reserved: `auto`, `default`).
 
-### Command Allowlist (Sandboxing)
+### Command Allowlist/Denylist (Sandboxing)
 
 ```bash
 # Only allow calendar + tasks commands for an agent
@@ -444,6 +445,18 @@ gog --enable-commands calendar,tasks calendar events --today
 # Same via env
 export GOG_ENABLE_COMMANDS=calendar,tasks
 gog tasks list <tasklistId>
+
+# Block specific subcommands using dot-notation
+gog --disable-commands gmail.send gmail search 'from:boss'  # allowed
+gog --disable-commands gmail.send gmail send --to a@b.com   # blocked
+
+# Block all subcommands of a command
+gog --disable-commands gmail gmail search 'from:boss'       # blocked
+
+# Same via env
+export GOG_DISABLE_COMMANDS=gmail.send,calendar.delete
+gog gmail search 'from:boss'  # allowed
+gog gmail send --to a@b.com   # blocked
 ```
 
 ## Security
@@ -1235,6 +1248,7 @@ All commands support these flags:
 
 - `--account <email|alias|auto>` - Account to use (overrides GOG_ACCOUNT)
 - `--enable-commands <csv>` - Allowlist top-level commands (e.g., `calendar,tasks`)
+- `--disable-commands <csv>` - Denylist commands using dot-notation (e.g., `gmail.send`)
 - `--json` - Output JSON to stdout (best for scripting)
 - `--plain` - Output stable, parseable text to stdout (TSV; no colors)
 - `--color <mode>` - Color mode: `auto`, `always`, or `never` (default: auto)

internal/cmd/enabled_commands.go

@@ -40,3 +40,35 @@ func parseEnabledCommands(value string) map[string]bool {
 	}
 	return out
 }
+
+func enforceDisabledCommands(kctx *kong.Context, disabled string) error {
+	return enforceDisabledCommandsForCommand(kctx.Command(), disabled)
+}
+
+func enforceDisabledCommandsForCommand(command, disabled string) error {
+	disabled = strings.TrimSpace(disabled)
+	if disabled == "" {
+		return nil
+	}
+
+	denyList := parseEnabledCommands(disabled)
+	if len(denyList) == 0 {
+		return nil
+	}
+
+	cmdParts := strings.Fields(command)
+	if len(cmdParts) == 0 {
+		return nil
+	}
+
+	// Check if any prefix of the command path is disabled
+	// e.g., ["gmail", "send"] checks "gmail.send", then "gmail"
+	for i := len(cmdParts); i >= 1; i-- {
+		prefix := strings.ToLower(strings.Join(cmdParts[:i], "."))
+		if denyList[prefix] {
+			return usagef("command %q is disabled (blocked by --disable-commands)", strings.Join(cmdParts[:i], " "))
+		}
+	}
+
+	return nil
+}

internal/cmd/enabled_commands_test.go

@@ -1,10 +1,121 @@
 package cmd
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestParseEnabledCommands(t *testing.T) {
 	allow := parseEnabledCommands("calendar, tasks ,Gmail")
 	if !allow["calendar"] || !allow["tasks"] || !allow["gmail"] {
 		t.Fatalf("unexpected allow map: %#v", allow)
 	}
 }
+
+func TestEnforceDisabledCommands(t *testing.T) {
+	tests := []struct {
+		name     string
+		disabled string
+		command  string
+		wantErr  bool
+	}{
+		{
+			name:     "empty disabled allows all",
+			disabled: "",
+			command:  "gmail send",
+			wantErr:  false,
+		},
+		{
+			name:     "whitespace-only disabled allows all",
+			disabled: "   ",
+			command:  "gmail send",
+			wantErr:  false,
+		},
+		{
+			name:     "exact match blocks command",
+			disabled: "gmail.send",
+			command:  "gmail send",
+			wantErr:  true,
+		},
+		{
+			name:     "parent blocks all children",
+			disabled: "gmail",
+			command:  "gmail send",
+			wantErr:  true,
+		},
+		{
+			name:     "parent blocks nested children",
+			disabled: "gmail",
+			command:  "gmail messages list",
+			wantErr:  true,
+		},
+		{
+			name:     "specific subcommand does not block sibling",
+			disabled: "gmail.send",
+			command:  "gmail search",
+			wantErr:  false,
+		},
+		{
+			name:     "specific subcommand does not block different parent",
+			disabled: "gmail.messages",
+			command:  "gmail send",
+			wantErr:  false,
+		},
+		{
+			name:     "case insensitive matching",
+			disabled: "Gmail.SEND",
+			command:  "gmail send",
+			wantErr:  true,
+		},
+		{
+			name:     "multiple disabled commands",
+			disabled: "gmail.send,calendar.delete",
+			command:  "gmail send",
+			wantErr:  true,
+		},
+		{
+			name:     "multiple disabled commands - second match",
+			disabled: "gmail.send,calendar.delete",
+			command:  "calendar delete",
+			wantErr:  true,
+		},
+		{
+			name:     "multiple disabled commands - no match",
+			disabled: "gmail.send,calendar.delete",
+			command:  "gmail search",
+			wantErr:  false,
+		},
+		{
+			name:     "empty command allowed",
+			disabled: "gmail.send",
+			command:  "",
+			wantErr:  false,
+		},
+		{
+			name:     "three-level command blocked by middle",
+			disabled: "gmail.messages",
+			command:  "gmail messages list",
+			wantErr:  true,
+		},
+		{
+			name:     "three-level command blocked by exact match",
+			disabled: "gmail.messages.list",
+			command:  "gmail messages list",
+			wantErr:  true,
+		},
+		{
+			name:     "three-level command - sibling allowed",
+			disabled: "gmail.messages.list",
+			command:  "gmail messages get",
+			wantErr:  false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := enforceDisabledCommandsForCommand(tt.command, tt.disabled)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("enforceDisabledCommandsForCommand() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}

internal/cmd/root.go

@@ -24,15 +24,16 @@ const (
 )
 
 type RootFlags struct {
-	Color          string `help:"Color output: auto|always|never" default:"${color}"`
-	Account        string `help:"Account email for API commands (gmail/calendar/chat/classroom/drive/docs/slides/contacts/tasks/people/sheets)"`
-	Client         string `help:"OAuth client name (selects stored credentials + token bucket)" default:"${client}"`
-	EnableCommands string `help:"Comma-separated list of enabled top-level commands (restricts CLI)" default:"${enabled_commands}"`
-	JSON           bool   `help:"Output JSON to stdout (best for scripting)" default:"${json}"`
-	Plain          bool   `help:"Output stable, parseable text to stdout (TSV; no colors)" default:"${plain}"`
-	Force          bool   `help:"Skip confirmations for destructive commands"`
-	NoInput        bool   `help:"Never prompt; fail instead (useful for CI)"`
-	Verbose        bool   `help:"Enable verbose logging"`
+	Color           string `help:"Color output: auto|always|never" default:"${color}"`
+	Account         string `help:"Account email for API commands (gmail/calendar/chat/classroom/drive/docs/slides/contacts/tasks/people/sheets)"`
+	Client          string `help:"OAuth client name (selects stored credentials + token bucket)" default:"${client}"`
+	EnableCommands  string `help:"Comma-separated list of enabled top-level commands (restricts CLI)" default:"${enabled_commands}"`
+	DisableCommands string `help:"Comma-separated list of disabled commands using dot-notation (e.g., gmail.send)" default:"${disabled_commands}"`
+	JSON            bool   `help:"Output JSON to stdout (best for scripting)" default:"${json}"`
+	Plain           bool   `help:"Output stable, parseable text to stdout (TSV; no colors)" default:"${plain}"`
+	Force           bool   `help:"Skip confirmations for destructive commands"`
+	NoInput         bool   `help:"Never prompt; fail instead (useful for CI)"`
+	Verbose         bool   `help:"Enable verbose logging"`
 }
 
 type CLI struct {
@@ -95,6 +96,11 @@ func Execute(args []string) (err error) {
 		return err
 	}
 
+	if err = enforceDisabledCommands(kctx, cli.DisableCommands); err != nil {
+		_, _ = fmt.Fprintln(os.Stderr, errfmt.Format(err))
+		return err
+	}
+
 	logLevel := slog.LevelWarn
 	if cli.Verbose {
 		logLevel = slog.LevelDebug
@@ -171,14 +177,15 @@ func boolString(v bool) string {
 func newParser(description string) (*kong.Kong, *CLI, error) {
 	envMode := outfmt.FromEnv()
 	vars := kong.Vars{
-		"auth_services":    googleauth.UserServiceCSV(),
-		"color":            envOr("GOG_COLOR", "auto"),
-		"calendar_weekday": envOr("GOG_CALENDAR_WEEKDAY", "false"),
-		"client":           envOr("GOG_CLIENT", ""),
-		"enabled_commands": envOr("GOG_ENABLE_COMMANDS", ""),
-		"json":             boolString(envMode.JSON),
-		"plain":            boolString(envMode.Plain),
-		"version":          VersionString(),
+		"auth_services":     googleauth.UserServiceCSV(),
+		"color":             envOr("GOG_COLOR", "auto"),
+		"calendar_weekday":  envOr("GOG_CALENDAR_WEEKDAY", "false"),
+		"client":            envOr("GOG_CLIENT", ""),
+		"enabled_commands":  envOr("GOG_ENABLE_COMMANDS", ""),
+		"disabled_commands": envOr("GOG_DISABLE_COMMANDS", ""),
+		"json":              boolString(envMode.JSON),
+		"plain":             boolString(envMode.Plain),
+		"version":           VersionString(),
 	}
 
 	cli := &CLI{}